1. Field of the Invention
The invention concerns a batten for looms.
2. Description of Related Art
More particularly, the invention is concerned with a batten which is equipped with, besides the batten legs, the batten beam and the reed, of a batten shaft which is designed as a counterweight.
More specifically, the invention concerns a batten wherein the center or axis of gravity of the batten (including possibly the counterweight) does not coincide with the swinging axis of the batten but is located at a defined distance underneath the swinging axis and/or the opposite side of the reed in relation with this axis.
In a preferred form, the batten according to the invention is designed in such a way that, besides the above recited characteristics, it has a minimum moment of inertia in relation to its center of gravity or axis of gravity.
Prior art looms are generally equipped with a batten composed of a batten shaft in a horizontal position, whereon batten legs, reed beams and the reed are mounted. Consequently, the center of gravity does not lie on or coincide with the swinging axis and the center of gravity is always located at the side of the reed in relation with the swinging axis in such a way that the center of gravity is generally located above the swinging axis.
It has also been suggested in the prior art to equip the batten with counterweights according to are general principles of balancing techniques which are based on the dynamics theory and according to which the counterweights are fitted on a swinging body in such a way that the center of gravity of the whole system is located on the swinging axis.
Another prior art solution comprises displacing the batten axis a quite large distance in relation to the swinging axis by the use of check flanges. This design is advantageous in the sense that the total batten weight remains approximately the same whereby the displaced batten axis plays the part of a counterweight and the batten legs generally have a hollow structure in order that the total weight of this balanced batten is not larger than the weight of an unbalanced batten. This embodiment is known for instance from the U.S. Pat. No. 4,075,048.
Although this well known design has the advantageous property of increasing slightly or not at all the total weight of the batten, it offers, however, the drawback of strongly increasing the batten moment of inertia about the swinging axis. It is well known indeed that the inertia of an object swinging around its center of gravity increases when its swinging axis is displaced, on one hand, proportionally with its mass and, on the other hand, proportionally to the square of the displacement distance. If thus the batten axis is displaced, an important and undesirable increase of the inertia moment of the batten occurs, as is already well known, even if the mass is not increased. This well known solution already mentioned has consequently the disadvantage of greatly increasing the driving torque for the batten.
Another system known in the prior art, the batten axis is designed in a special way and is mainly made of a solid cylindrical shaft which is eccentrically located, whereby the center of gravity of the whole batten remains located within or on the geometrical periphery of the batten shaft. The objective of this solution was not to keep the same mass value, but to get a minimum inertia moment around the swinging axis. In a specific embodiment, the axis of gravity and the swinging axis are in coincidence with the geometrical periphery of the batten shaft.
In the latter case, as well in the previous case mentioned above, whereby a total balancing is carried out, it has been stated that nearly no horizontal dynamic forces are applied to the machine. However, the dynamic vertical forces which act on the floor under the loom are quite large and sometimes not acceptable. In weaving factories, where the looms are located on floors above ground level, for instance in an old factory building, these conditions may be quite dangerous to the building stability.
Further research resulted however in the discovery that a more balanced effect of the forces acting on the batten for reacted thereby could be achieved by arranging the center of gravity of the batten under the swinging axis. This design will be described hereafter and illustrated by a few alternative solutions. More specially the force distribution at the supporting points of the loom will be described.